Colorimetric and ratiometric aggregation assay for streptomycin using gold nanoparticles and a new and highly specific aptamer

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• 作者：Vahid Soheili ; Seyed Mohammad Taghdisi ; Mohammad Hassanzadeh Khayyat…
• 刊名：Microchimica Acta
• 出版年：2016
• 出版时间：May 2016
• 年：2016
• 卷：183
• 期：5
• 页码：1687-1697
• 全文大小：731 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Analytical Chemistry
  Inorganic Chemistry
  Physical Chemistry
  Characterization and Evaluation Materials
  Monitoring, Environmental Analysis and Environmental Ecotoxicology
  
• 出版者：Springer Wien
• ISSN：1436-5073
• 卷排序：183

文摘

Aptamers specific for the antibiotic streptomycin were identified by a modified SELEX procedure that employs magnetic beads. After eight rounds of selection, twenty-six aptamers were identified and clustered into seven groups according to similarities in their sequences. The binding constant of three sequences from different groups were determined by colorimetric assays using unmodified gold nanoparticles (AuNPs). These most suitable aptamers were then truncated, and finally a 23-base sequence was identified that has the highest affinity (K_d = 132.3 nM) and selectivity. The assay was employed to analyze streptomycin residue in raw milk samples by ratiometric spectrophotometry at 520 and 660 nm, respectively. The analytical range extends from 180 to 1000 nM, and the LOD is 47.2 nM which is better than that of HPLC (4 μM). The interaction between aptamer and streptomycin was studied by molecular modeling. In our perception, this colorimetric assay provides a viable method for fast analysis of streptomycin in raw milk.